Figure 2
From: ZnT2 is a critical mediator of lysosomal-mediated cell death during early mammary gland involution
Adenoviral expression of ZnT2 increases LCD and apoptosis and initiates premature involution.
(a) Mammary glands from AdLacZ and AdZnT2 mice were digested in nitric acid and Zn concentration was measured by atomic absorption spectroscopy. Data represent mean μg Zn/g tissue ± SD; n = 9/group, **P < 0.001. (b)–(c) Zn concentration of lysosome- and mitochondria-enriched fractions isolated from AdLacZ- and AdZnT2-expressing mammary glands. Fractions were digested in nitric acid and concentration was measured by atomic absorption spectroscopy. Data represent mean μg Zn/mg protein ± SD; n = 4/group, **P < 0.001 and ***P < 0.0001. (d) TUNEL staining in AdZnT2-transduced mammary glands and compared with mammary glands transduced with AdLacZ. Data represent percentage of TUNEL positive staining cells ± SD; n = 5 mice/group, ***P < 0.0001. (e) Immunofluorescent staining of cathepsin B and DAPI in AdLacZ- and AdZnT2-expressing mammary glands. Scale bars = 100 μm. (f) Cathepsin B activity in lysosome-enriched and cytosolic fractions isolated from mammary glands of AdLacZ and AdZnT2 mice. Data represent fold increase in activity ± SD; n = 4 mice/group, **P < 0.001. (g) Whole mounts from mammary glands transduced with AdLacZ (top) showed normal mammary gland morphology with expanded alveoli during lactation. In contrast, mammary glands expressing the ZnT2 adenovirus (AdZnT2, bottom) had disintegrated acini in which the terminal end buds were considerably regressed. Scale bar = 2 mm. (h) Immunofluorescent staining of HA and pStat3 from mammary glands transduced with AdLacZ or AdZnT2. HA fluorescence was only detected in sections from mammary glands transduced with AdZnT2-HA, which also expressed pStat3. Scale bars = 100 μm.
